Concrete pavement cutting machine

ABSTRACT

Pavement cutting machine with a carriage frame having a cutter for cutting grooves in a pavement. The carriage frame has front wheels in front of the cutter and rear wheels at the rear of the cutter, an auxiliary wheel being provided with a support which retains the bottom of its periphery above and out of contact with the pavement in the absence of an abrupt drop in the level of the pavement. The auxiliary wheel contacts the pavement to limit the depth of cut of the cutter when the wheel in front of the cutter encounters an abrupt drop in the level of the pavement.

United States Patent 191 [1 1 3,724,900 Hatcher et al. [451 Apr. 3, 1973 [541 CONCRETE PAVEMENT CUTTING 3,608,969 9/1971 Fowkes ..299/39 MACHINE Inventors: Cecil W. Hatcher, West Covina; Gene Warner, Whittier. both of Calif.

Appl. No.: 209,118

Assignee:

US. Cl. ..299/39, 51/176 Int. Cl ..E0lc 23/09 Field of Search ..299/394l; 51/176 References Cited UNITED STATES PATENTS 7/1961 Hatchet ..299/39 Primary ExaminerErnest R. Purser Attorney-William E. Beatty 1 ABSTRACT Pavement cutting machine with a carriage frame having a cutter for cutting grooves in a pavement. The carriage frame has front wheels in front of the cutter and rear wheels at the rear of the cutter, an auxiliary wheel being provided with a support which retains the bottom of its periphery above and out of contact with the pavement in the absence of an abrupt drop in the level of the pavement. The auxiliary wheel contacts the pavement to limit the depth of cut of the cutter when the wheel in front of the cutter encounters an abrupt drop in the level of the pavement.

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HrmRA/E/ PATENTEUAFR 3 I975 SHEET 7 BF 7 CONCRETE PAVEMENT CUTTING MACHINE CROSS-REFERENCE TO RELATED APPLICATIONS PAVEMENT CUTTING MACHINE, Ser. No. 119,476, filed Mar. 1, 1971 by Cecil W. I-Iatcher et al. and now US Pat. No. 3,703,316; and CONCRETE PAVEMENT CUTTING MACHINE, Ser. No. ll8,909, filed Feb. 25, 1971 by Cecil W. Hatcher et a1. and now US. Pat. No. 3,697,135.

BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to concrete pavement cutting machines and has particular reference to machines having axially spaced, rotatable, abrasive disks engageable with the pavement to cut anti-skid grooves therein.

2. Description of the Prior Art Concrete cutting machines have been employed heretofore to cut closely spaced grooves in the pavement to reduce skidding tendencies of vehicles traveling thereon. Certain types of such machines have a carriage wheel in front of the cutter. If the pavement has an abrupt drop as sometimes occurs at a joint in the pavement, the cutter drops correspondingly to cut deeper grooves than required. This produces undesirable wear on the cutter blades and also produces grooves which are too deep to meet the required specification.

SUMMARY OF THE INVENTION A principal object of the present invention is to limit the depth of cut of the cutter when a wheel in front of the cutter encounters an abrupt drop in the level of the pavement.

The invention provides an auxiliary wheel rotatable on an axis below and substantially parallel to the axis of the cutter shaft, with means supporting the auxiliary wheel with the bottom of its periphery above and out of contact with the pavement in the absence of an abrupt drop in the level of the pavement. The machine includes a front wheel means in front of the cutter, the auxiliary wheel limiting the depth of cut of the cutter when the front wheel means encounters an abrupt drop in the level of the pavement.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side elevational view of the machine described and claimed in U. S. Ser. No. 118,909 provided with the auxiliary wheel of the present invention.

FIG. 2 is a sectional view on line 22 of FIG. 1, looking in the direction of the arrows.

FIG. 3 is an enlarged side elevational view, with parts broken away, of the frame, bracket and adjustable auxiliary wheel as seen on one side of the machine, a similar bracket and auxiliary wheel, not appearing in this figure, being provided on the other side of the machine. This view shows the auxiliary wheel in elevated position.

FIG. 4 is a side elevational view, with parts broken away, of the parts shown in FIG. 3, with the front wheel encountering a drop in the pavement and with the auxiliary wheel in contact with the pavement.

FIG. 5 is a sectional view on line 5-5 of FIG. 3, looking in the direction of the arrows.

FIG. 6 is an exploded perspective view of the auxiliary wheel and its bracket support.

FIG. 7 is a sectional plan view taken substantially along line 77 of FIG. 1.

FIG. 8 is a fragmentary perspective view of one of the cutting depth control arms.

FIG. 9 is a fragmentary sectional side view showing one of the control arms in depth-limiting position, with an adjustable wheel in front of the cutter as used in cutting anti-skid grooves.

FIG. 10 is a side elevational view of the machine shown in U. S. Ser. No. 119,476 provided with the auxiliary wheel of the present invention.

FIG. 11 is a sectional view on line l11 I of FIG. 12, looking in the direction of the arrows and showing the auxiliary wheels above the level of the pavement, these wheels appearing only at the inner end of each cutter.

FIG. 12 is a sectional view on line l2l2 of FIG. 11, looking in the direction of the arrows.

FIG. 13 is an enlarged, exploded perspective view of the auxiliary wheel assembly, with parts broken away.

FIG. 14 is a plan view of the assembly of FIG. 16.

FIG. 15 is a vertical sectional view showing a portion of FIG. 11 and illustrating the auxiliary wheel in contact with the pavement.

FIG. 16 is a partial perspective view of the grooving trailer assembly with the auxiliary wheels at the inner end of each cutter.

FIG. 17 is a vertical sectional view on line 17-17 of FIG. 14.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Machine of FIGS. 1 through 9 Referring to the drawings, the machine comprises, in general, a truck 1 1 coupled to a cutter vehicle 11'. The truck 11 is supported by a single set of coaxial drive wheels, one of which is shown at 12. An upright mast assembly 13 is attached to the truck frame 14 by brackets 15 and comprises inwardly facing U-channel members 16 and 17, FIG. 7, along which a carriage 18 is movable. The carriage comprises a vertical plate 20 carrying two vertically spaced rollers 21 and 22 which move along the channel member 17, and two similar rollers which move along the channel member 16, upper roller 21' appearing in FIG. 7. The plate 20 is welded or otherwise attached to the rear cross member 23' of a cutter supporting frame 23. When the vehicle 11 is being pushed by truck 11, side sway of vehicle 11' is prevented as the slide couplings including channel members 16 and .17 are laterally spaced apart on opposite sides of the longitudinal axis of the truck 11 and vehicle 11'.

An engine 24 is carried by the truck 11 and is connected to the drive wheels 12 through a drive train comprising a fluid coupling 24', a multi-speed transmission 25, and a differential 26.

As shown in FIG. 1, a hydraulic cylinder 27 is secured at 28 to the lower end of the mast assembly 13, and its piston rod 27' is connected at 30 to a bracket 20 fixed to the carriage plate 20, whereby extension of the piston will raise the rear end of the frame 23 which tilts about the horizontal axis of the front wheels 38, 40.

The aforementioned truck 11 preferably comprises a conventional forklift truck from which a second set of wheels and the usual fork attached to the carriage have been removed. A seat 31 is provided for the operator, and various controls, including a steering wheel 32, are mounted on an upright part of the truck frame within easy reach of the operator.

The frame 23 comprises spaced side frame members 33 and 34, FIG. 7, and integral cross members 23', 35, 36 and 37. The frame 23 is supported at its forward end by spaced, steerable wheels 38 and 40, which support an axle 41 suitably attached to the frame 23. A poweroperated steering linkage is provided, comprising cross links 42 and 43 connected between the bearing supports of the wheels and a crank 44 pivoted at 45 and operable by the piston of a hydraulic cylinder 46 mounted on the cross member 36.

A rotatable concrete cutter, generally indicated at 47, is provided, comprising a plurality of abrasive cutting disks 48 secured on a cutter shaft 50. The latter is rotatably mounted in bearings 51 and 52 suitably secured to pillow blocks 53 and 54 integral with the side frame members 34 and 33, respectively.

An engine 55 is mounted on the forward part of the frame 23 and drives the cutter through a drive train including a clutch 56 and a differential unit 57, output shaft 58 of which is joumaled in bearings 60 and 61 supported by the frame 23. Pulleys 62 and 63 are secured to the outer ends of the shaft 58 and drive pulleys 64 and 65 secured to the cutter shaft 50 through sets of drive belts 66 and 67, respectively. In order to adjust the tension in belt 66 and take up the slack, a longitudinally adjustable idler pulley 142 is carried by the frame 23.

The cutter 47 is selectively driven by engaging the clutch 56; and for this purpose, the clutch is controlled by a hydraulic clutch engaging cylinder 68 under control of the truck operator.

Means exclusive of the lift cylinder 27 are provided to accurately limit the depth of cut and to provide an accurate adjustment which may be preset according to the depth of cut desired. For this purpose, a pair of arms 70 and 71, FIGS. 1, 7, 8 and 9, are pivoted on a horizontal axis at 72 and 73, respectively, on the side frame members 33 and 34, vertically above the axis of shaft 50.

The arms 70 and 71 are guided at their upper horizontal end portions like 70 in inverted U-shaped members 74 and 75 welded to the carriage plate 20 and to cross member 23. Adjustable limit screws 76 and 77 are threaded in the members 74 and 75 to engage end portions like 70' and limit the vertical movement of the arms. Lock nuts, like nut 78, are provided to lock the screws 76 and 77 in different adjusted positions. When the frame 23 is raised to its transporting position with cutter 47 and wheels 81, 82 in elevated position, arms 70 and 71 engage the top of the plate 20 and are thus raised, with their wheeled supports, like 80, with the frame. A wheeled support, like support 80, is mounted on each of the arms 70 and 71, and each comprises a pair of wheels 81 and 82 rotatably mounted at opposite ends of a wheel truck 83 pivotally attached at its center at 84 to a column 85 integral with and depending from the respective arm.

By adjusting limit screws 76 and 77 relative to each other, the frame 23, and hence the cutter 47, may be tilted slightly or not in a transverse direction relative to the level of the pavement.

From the above, it will be seen that, when the rear end of the frame 23 is lowered by the hydraulic cylinder 27, the cutting disks 48 will engage the surface of the pavement. At substantially this time, the wheels 81 and 82 also engage the pavement, rocking the arms and 71 upward on pivots 72, 73 until arrested by the limit screws 76 and 77. The screws 76 and 77 are preferably preadjusted so that the cutting disks 48 will cut to a predetermined depth, as indicated at 86, FIG. 1. Therefore, a fine and accurate control of the lift cylinder 27 is not required.

When hydraulic pressure is applied below the piston of the cylinder 27, to extend piston rod 27', the carriage 18 will be driven up along the mast assembly. The truck frame 14 will remain parallel to the frame 23, due to the upright sliding connection between them provided by the mast assembly 13.

Hydraulic power for enabling remote control of the steering cylinder 46, clutch control cylinder 68 and lift cylinder 27 is derived from a hydraulic pump driven by the truck motor 24. For this purpose, the steering wheel at 32 controls a valve 91 connected in a fluid circuit between the pump 90 and the opposite ends of the steering cylinder 46, as well known. A lift cylinder control valve, not shown, within reach of the operator, is connected in circuit between the pump 90 and opposite ends of the lift cylinder 27. Likewise, a clutch control valve, not shown, also within reach of the operator, is connected in circuit between the pump 90 and opposite ends of the clutch control cylinder 68.

The truck transmission 25 is controlled by a gear shift lever 94, FIG. 1, whereby the machine may be selectively driven at a slow rate of speed, as when cutting, or a fast rate when transporting from one place to another.

To cut anti-skid grooves in a pavement, the cutter 47 has abrasive disks spaced apart, i.e., with a spacing on the order of .375 inch between adjacent disks. in this case, see FIG. 9, a downwardly curved bracket, like bracket 96, is secured to each of the arms 70 and 71 by bolts like 97. A wheeled support comprising a wheel 98 is rotatably mounted on an arm 100 pivoted at 101 to each bracket 96, and extends directly in front of the cutter 47. An adjustment screw 102 is threaded through the arm 100 and engages the bracket 96 to swing the arm 100 relative to its bracket whereby to provide a height adjustment for the rear of the associated arm 70 or 71 independently of the stop screws 76 and 77, which, in this case, are preferably backed off.

FIG. 9 shows the screw 102 at one extreme of its adjustment wherein the extension 70 of arm 70 rests on the top of the carriage plate 20.

As the cutter frame 23 is lowered, the wheel 81, 82 and 98 engage the pavement of opposite sides of the cutter, and by adjusting the screw 102, the depth of cut of the groove-cutting disks can be accurately adjusted without requiring close attention by the operator.

The abrasive disks are cooled by a spray of water forced through orifices of 103 spaced along a pipe 104 supported from the side frame members 33 and 34 by brackets 106 and 107. An indicator rod 108 is suspended from the front end of the frame 23 to aid the operator in steering the machine along a line or previous cut or grooved section of the pavement. Auxiliary Wheels of Machine of FIGS. 1 through 9 Auxiliary wheels are provided to limit the depth of cut if the wheels like 98 which are in front of the cutter 47 advance to a position where the pavement drops as indicated at 110 in FIGS. 3 and 4. An auxiliary wheel assembly is provided at each end of the cutter 47 as indicated at 111 and 112 in FIG. 2, the assembly 111 appearing in FIG. 1. Assembly 111 has a wheel 113 rotatable on axle 113, and assembly 112 has a wheel 114 rotatable on axle 114. Both of these wheels are in elevated position with a clearance such as one thirtysecond to one-sixteenth inch above the pavement under normal conditions, in the absence of a drop-off in the pavement. Assembly 111 is mounted on and carried by the side frame member 34, and the assembly 112 is mounted on and carried by the side frame member 33, these members forming sides of the frame 23. As both of the assemblies 111 and 112 are the same, only one of them will be described.

The assembly 111 is shown in perspective exploded view in FIG. 6 and comprises a horizontally extending U-shaped bracket or frame 115, the legs 116 and 117 thereof terminating in vertical plates 118 and 119, respectively. Each plate has bolt holes like 120 to receive bolts like 121 in FIG. 3 for fastening the plate to the side frame member 34. Welded to the underside of the center of bracket 115 in a base plate 122. Plate 122 has vertical sides 123 and 124 spaced apart to slidably receive the adjustable plate 125. The space between the sides 123 and 124 is substantially the same as the width of the plate 125. Plate 125 is mounted on and forms a part of the support 126 for the auxiliary wheel 113. The base plate 122 has bolt holes 127 and 128 in vertical alignment at one side of the plate and bolt holes 129 and 130 in vertical alignment at the other side of the plate. The holes 127 and 128 match the slots 131 and 132 in plate 125, and the holes 129 and 130 match the slots 133 and 134 at the other side of plate 125. A bolt like 135 is provided for each of the four sets of holes in the plates 122 and 125, the slots 131 to 134 permitting vertical adjustment of the auxiliary wheel 113 to a desired height. For all positions of adjustment, the axis or axle 113' of the wheel 113 is below and in a vertical plane containing the axis of cutter shaft 50; and a similar relation applies to the adjustment of wheel 1 14.

In order to further support the wheel 113 and hold it in adjusted position, the top 136 of the wheel support 126 has arising therefrom a vertical bolt 137 which fits in the notch 138 in a bracket 139 extending horizontally from and welded to the underside of the center of bracket 115. Suitable nuts and washers indicated at 140 are provided to engage the upper and lower sides of the bracket 139 and hold the bolt 137 in adjusted position. A brace 141 fills the space between the base of bolt 137 and the plate 125 and is welded thereto and to the top 136 of the wheel support 126.

Machine of FIGS. through 17 There is shown in FIG. 10 a tractor-trailer vehicle, generally indicated at 210, comprising a tractor, indicated generally at 212, which is provided with a typical cab 214 and a Diesel or similar engine 216 mounted at the front end of the tractor frame 218. The frame 218 is provided with a'swivel bed or hitch 220 for an operable connection between the tractor and a tandem trailer. Tractor 212 is movably supported by a set of front wheels 222 for steering the vehicle 210 and a back set of drive wheels 224.

However, there is included means for disengaging the engine power from the rear drive or traction wheels 224 to engage a hydraulic drive system when required. This forms no part of the present invention and its details are disclosed and claimed in U. S. Ser. No. l l9,476.

There is operably connected to the swivel bed or hitch 220 of the tractor 212 a first tandem trailer unit 226 and a second tandem trailer unit 228 which is operably connected to said first trailer unit 226 by a swivel bed or hitch 229, supported on the rear of said first trailer unit. The first trailer unit 226 includes a grooving machine having a rotary cutter assembly 245, having a hitch 225 with the frame structure 230 which in turn has a hitch 220 with the tractor 212.

The trailer unit 226 comprises a carriage or frame structure 230 having a somewhat Z-shaped configuration which includes a horizontal box framework 232 having a mating member 233 for the swivel bed 220 and a platform 234. Positioned rearwardly of the platform 234 and attached to frame 232 are a pair of parallel vertical beams 236, 236 spaced apart sufficiently to receive a transverse support bar 237, as seen in FIGS. 14 and 16. The beams 236, 236' are secured to the box frame 232 intermediate their ends. Rearwardly disposed from the beams 236, 236' is a second pair of matching beams 238, 238, the beams 236 and 238 being interconnected by overhead horizontal girder member 239, and beams 236' and 238' being similarly interconnected by an overhead horizontal girder member 239'. The girders 239, 239' have suitable transverse supports shown as l-beams 241 and 243, see FIG. 10, welded at their ends into the girders 239, 239. Attached to the lower portion of the rear vertical beams 238, 238 is a set of parallel frame members like 240 having a platform to support the second swivel bed or hitch member 229 (FIG. 10). To carry the rear portion of the frame structure 230, there is provided a set of tandem wheels 242 positioned directly under the swivel bed member 229 whereby the front end of the second trailer 228 is operably connected thereto. The trailer 228 has rear wheels 365.

Referring to FIGS. 10, 14 and 16, there is provided a rotary cutter assembly 245 operably mounted within the frame structure 230 of the carriage, said cutter assembly 245 comprising an independent drive engine 246 for operating a pair of rotary cutter units, indicated generally at 248 and 250, respectively. There is also provided means for supporting one of said cutting units in advance of the other, with the inner ends of said cutter units in substantial alignment. The supporting means comprises a U-shaped frame structure 252, as seen in FIGS. 14 and 16, hingedly connected, as indicated at 253, at its forward open end to a header 254 having a hitch 255 which includes an upper ball member 255a secured to the header 254 and a cooperating lower mating socket member 255b horizontally projecting from and secured to the transverse support bar 237. Oppositely and rearwardly disposed from the header 254 is the bight portion 257 of the U-shaped frame 252, said bight 257 being a rear transverse member having mounted thereon a slide 256 in the form of a cylindrical pin which is rotatably received in and guided for vertical and pivotal movement by vertical spaced angle irons providing slot means 258 carried by bracket 240' depending from frame members 240, 240a, see FIGS. 10 and 16. The slot means'258 prevents lateral movement of frame 252 with respect to, the frame structure 230, while permitting rocking movement about a horizontal axis.

The beams 236, 236', see FIG. 16, have an angle bracket 249, 249, respectively, extending over the header 254 at opposite sides of its longitudinal axis to limit pivotal movement of header 254 about that axis, particularly when acted on by hydraulic cylinders 296 and 297, described later.

Due to the ball and socket hitch 255 at one end of the frame 252 and the slide 256 rotatably received in slot 258, the frame and cutter assembly 245 together are capable of being angularly adjustable about a horizontal axis aa, seen in FIG. 14, said hitch and said slide permitting the cutter units to be readily adapted to an inclined surface, when required.

An independent engine 246 is used to operate the cutter units 248 and 250, said engine being mounted to the floating U-shaped frame 252 adjacent the bight portion 257 of the U by transverse channel members 259 secured at their ends to the side members 260, 260' of the frame 252. The power output shaft 261 of the engine 246 is provide at one end with a pulley and belt arrangement 262 appearing in FIG. 10 to drive the pulley 271 of cutter 248, see FIG. 14. The engine also drives a similar pulley and belt arrangement, not shown, to drive the pulley 273 of cutter 250, FIG. 14.

As mentioned above, the cutter units 248 and 250 are so arranged that one assembly is positioned forwardly of the other cutter assembly with the endmost disks of their inner ends 275 and 276 spaced apart the same distance as the spacing between adjacent disks (FIG. 14). Each cutter unit 248 and 250 comprises a plurality of evenly-spacedapart cutter disks having identical diameters and secured on the shafts 272 and 274 for rotation therewith. The disks are generally provided with diamond bits for cutting hard materials, such as cement and concrete.

The shafts 272 and 274 are journaled at their outer ends by universal bearings 279 and 280, respectively, said bearings being supported within dual pillow blocks 282 and 283 along the rearward section of the side members 260, 260' of the frame 252. However, the inner ends 275 and 276 of cutter units 248 and 250, respectively, have their shafts 272 and 274 joumaled in bearings 284 and 285, respectively, supported within dual blocks 286 and 287, respectively.

As shown in FIGS. 14 and 16, a pair of parallel floating beams 288 and 290 are provided along the inner longitudinal length of the frame 252 for supporting the inner ends of each cutter unit. Each floating beam 288 and 290 is independently hinged to the header 254 by brackets 292 and bolts 293, acting as hinge pins, at the forward end thereof. The opposite or rear free end of each beam 288 and 290 is movably received within the U-shaped brackets 294 and 295, respectively. Said brackets are secured to the rear bight portion 257 of the frame member 252. It should be particularly noted that each beam is capable of being actuated individually with respect to each other, as well as with respect to the floating frame 252.

As shown in FIG. 16, the inner support block 286 for the inner end of shaft 272 is mounted on beam 290, whereas the block 287 for the inner end of shaft 274 is carried by beam 288, with the inner ends of those shafts in overlapping relation as also shown in FIGS. 14 and 16. This construction makes it possible to preserve between the endmost disk of the cutter assembly 248 and the adjacent endmost disk of the cutter assembly 250, at the inner ends of those cutters, for groove cutting purposes,a spacing which is substantially the same as the spacing between the adjacent disks on each cutter assembly.

As shown in FIG. 16, the frame 252 and the rotary cutting assembly 245 are lifted or lowered by means of a pair of hydraulic cylinders 296 and 297 which are hingedly connected at their lower ends 298 and 298 to the rear end of frame 252, and their upper ends 299 and 299' are hingedly connected to the underside of a transversely-extending beam 300 which is secured to the rear vertical beams 238, 238' of the frame structure 230. The bight or rear end 257 of frame 252 with the cutter assemblies 248 and 250 pivots about a horizontal axis passing through the hinge 253 and the hinge pins 293 of the beams 288 and 290. Since the tank trailer 228 is loaded with a dead weight of a large quantity of water, the frame structure 230 and the upper ends of cylinders 296 and 297 are held down from any vertical movement thereof when the cylinders 296 and 297 are activated, when the cutter assemblies 248 and 250 are in working engagement with the pavement. The force of the cylinders 296, 297 butt against the over-all weight of the tank which becomes an effective opposing force against the lifting effort of the cylinders 296 and 297. Not only can the frame 252 be adjusted vertically, but it can also be tilted at an angle through the longitudinal axis aa (FIG. 14) by adjusting the hydraulic cylinders 296, 297.

There is hingedly connected at the free or rear ends of beams 288, 290 hydraulic cylinders 301 and 302, respectively, for operating the rear end of each floating beam in different or similar vertical displacements. The hydraulic cylinders 301 and 302 are hingedly supported above the adjacent floating beams 288 and 290, respectively, by upside-down L-shaped brackets 303 and 303a which are fixedly secured to the rear 257 of the floating frame 252. The inner ends of the cutter units 248 and 250 can be positioned at a greater elevation than their outer ends to fit a convex road surface. The inner ends can also be adjusted lower than the outer ends to fit a concave road surface. Therefore, by adjusting the floating beams 288 and 290, the inner ends of the cutters may be raised or lowered with respect to their outer ends to substantially fit either a convexity or a concavity in the pavement.

When it is desired to move to a different location and travel at comparatively high speed with the cutter assemblies 248 and 250 in elevated position, the cylinders 296 and 297 are operated to raise the rear end 257 or frame 252, and in so doing, the outer'ends of the cutter assemblies are raised, their inner ends and the floating beams 288 and 290 being raised by reason of the brackets 294, 295. The brackets 294, 295 are carried by the frame member 257 and underhang the beams 288 and 290 to lift them when the rear end 257 of the frame is lifted. Brackets 294 and 295 are open at their tops to permit the upward movement of the beams 288 and 290 under working conditions, the brackets 294 and 295 then being in a lowered position free from supporting relation with the beams 288 and 290 which are then floated. The operator can adjust the pressure on the cylinders 301 and 302 to adjust the beams 288 and 290 and the inner ends of the cutter assemblies so as to suit working conditions and obtain a uniform depth of groove with resulting maximum length of life of the cutter disks.

As shown in FIGS. 10 to 12, the rotary cutter assembly 245 is provided with a continuous flow of liquid coolant which consists, generally, of water supplied from cell 362a of tank 244 of the end trailer 228. This water coolant is pumped by a pumping means 308 which is located at the front end of the tank 244 and is provided with a pair of flexible conduits, or hoses, 310 and 311 (FIG. 12) interconnected to separate spray nozzle means, indicated generally at 312 and 312. The hoses 310 and 311 are attached to the lower portion of side members 260, 260, respectively, of the frame 252. The hoses are operably connected to individual spray nozzle means 312 and 312. The nozzle means 312 and 312 are identical and both comprise a tubular conduit or manifold 314 having a plurality of spray nozzles 316, see FIG. 11, spaced along the side of the conduit facing the cutting edge of the blades 278, 278 as they contact the pavement during cutting thereof, thereby spraying water for coating the blades or disks of the cutting units 248 and 250, respectively. Details of the liquid coolant system form no part of the present invention and are disclosed and claimed in U. S. Ser. No. 119,476.

In order to supply a continuous, uninterrupted flow of water to the blades 278, 278', there is provided a vacuum system, generally indicated at 330 in FIG. 10. This system is used to return the water, along with the sludge material created by the cutting of the pavement, to the tank 244. The vacuum system comprises a vacuum pump 332 mounted to the end tank trailer 228. This pump is operated by motor 334. A vacuum is pulled from within the tank 244 through an outlet passage 336 located in the front upper wall of the tank cell 262a. As the pressure within the tank 244 is reduced by the vacuum system 330, a flow of water and sludge is createdbetween the cutting assembly 245 and tank 244. This flow is accomplished by establishing a vacuum chamber 340 which is defined by a flexible and elastic shroud, indicated generally at 342, having a somewhat rectangular wall or curtain 344 secured to and depending from frame 252. Said chamber also includes an upper shield partition 345 to seal or close the top of the vacuum chamber 340. The lower edges 349 of the side walls 344 of the vacuum chamber 340 form a sealing contact with the pavement around the cutting units and the spray nozzles. Included within the vacuum chamber 340 is a plurality of suction nozzles 346 which are operably connected to a rectangular manifold 347 connected to conduits like 350, 352 and 360 in FIG. 10 which lead to tank 244 for returning the water and sludge to said tank. Details of the vacuum system form no part of the present invention and are disclosed and claimed in U.S. Ser. No. 119,476.

For groove cutting purposes, each end of each cutter 248 and 250 is provided with a depth control device. For this purpose, as indicated in FIG. 14, cutter unit 248 has at its opposite ends the depth control devices 384 and 384a. Cutter unit 250 at its opposite ends has a depth control device 385, 385a. Each depth control device is carried by a support bracket like 386 welded to the frame 252 for the outer ends of the cutters and welded to the floating beams 288 and 290 for the inner ends of the cutters.

All four of these depth control devices for groove cutting are alike; and one of them, namely 385 at the outer end of cutter 248, is shown in elevation in FIG. 17 wherein the frame member 260 has a bracket 386,

the bolt 389 acting as a pivot support for the top of an inverted U-shaped rocker arm 388 having depending arms 388a and 388b. Arm 388a is at the front of the cutter 248 and terminates in a roller or wheel 390 which rides on the pavement ahead of the cutter. Arm 1588b extends behind the cutter and has a pivotal support at 394 for an adjusting arm 392 which terminates at its lower end in a roller or wheel support 393 which rides on the pavement behind the cutter. The angular position of arm 392, and hence the depth that the cutter can cut into the pavement, is controlled by operating the adjusting screw 396 mounted in the arm 392 and bearing against an abutment 383 on arm 388b.

As shown in FIG. 12, bracket 386 is welded to frame member 260 and includes upright plates 457 and 458 spaced apart to receive the top of the rocker arm 388 which is held in position by bolt 389 as described above.

The depth control shown in FIG. 17 makes it possible to keep a very close tolerance on the depth of the kerf being out, even when the surface of the pavement 304 raises or lowers during a cutting pass. Since the center of the cutting unit is intermediate that of the two rollers 390, 393, any raising or lowering of a roller with respect to the other roller will cause only a slight rise to the cutting area of the blade 278. That is, if the rollers 393 on the rearward side of the blades are thus one inch above the level pavement, then the cutter axis is raised only one-half the amount because of the arms involved. It should be noted, at this time, that the above description is with respect to the grooving operation of the machine.

As disclosed and claimed in U.S. Ser. No. 119,476, there is provided a separate means for laterally adjusting the position of frame 252 by repositioning hitch 255 and the slot means 258, which allows the shifting of the outer ends of the cutter units to be positioned closely adjacent to a curb.

Auxiliary Wheels of Machine of FIGS. 10 through 17 As shown in FIG. 14, cutter 248 has an auxiliary wheel device similar to that described in connection with FIGS. 1 to 9 and as appearing in FIG. 15, as indicated at 400 at the inner end only of this cutter. Similarly, cutter 250 has an auxiliary wheel device 401 at the inner end only of this cutter. As shown in FIG. 13, the so-called pillow block 286 is in the form of a hollow rectangular tube of structural steel, open at both ends and having four tapped holes as indicated at 402 each to receive one of the four bolts indicated at 403 to clamp the slidable plate 404 in adjusted position on the base plate 405. As shown in FIG. 13, the outer end of cutter shaft 272 terminates behind the plate 404, which makes it possible to support the plates 404 and 405 on the floating beam 290 which carries the bearing 284 for the shaft 272. Plate 404 has an auxiliary wheel 406, and the axis of its axle 407 is in the same vertical plane with the axis of cutter shaft 272. The auxiliary wheel device 400 has a bolt 408 and nuts 409 for a bracket 410, similar to the corresponding items previously described in connection with FIGS. 1 to 9. The auxiliary wheel device 401 is similar to the device 400 and is carried by the floating beam 288, as shown in FIG. 14. i

The operation of the auxiliary wheel devices 400 and 401 in the case of FIGS. to 17 is similar to that described in connection with FIGS. 1 to 9, the auxiliary wheel like 406, see FIG. 15,-contacting the pavement to limit the depth of cut in the case where the depth control wheel like 390 drops in a hole or depression in the pavement as indicated at 411. Otherwise, the bottom of the periphery of the auxiliary wheel is out of contact with the pavement.

The invention as its attendant advantages will be understood from the foregoing description; and it will be apparent that various changes may be made in the form, construction and arrangement of the parts of the invention without departing from the spirit and scope thereof or sacrificing its material advantages, the arrangements hereinbefore described being merely by way of example, without restriction to the specific forms shown or uses mentioned, except as defined in the accompanying claims.

We claim:

1. A pavement cutting machine comprising a carriage having a longitudinal axis, a frame member associated with said carriage, said frame member having a cutter having a shaft extending transversely of said axis, said carriage having front wheel means in front of said cutter and rear wheel means at the rear of said cutter, auxiliary wheel means including an auxiliary wheel rotatable on an axis below and substantially parallel to the axis of said cutter shaft, and means for supporting said auxiliary wheel with the bottom of its periphery above and out of contact with the pavement, in position to contact the pavement and limit the depth of cut of said cutter when said front wheel means encounters an abrupt drop in the level of the pavement.

2,. Machine according to claim 1, said supporting means for said auxiliary wheel means comprising means for adjusting the vertical position of 'said auxiliary wheel means to a position slightly above a plane tangent to the bottom of said front and rear wheel means.

3. Machine according to claim 1, said supporting means for said auxiliary wheel means comprising bracket means carried by said frame member for supporting said auxiliary wheel beyond the outer end of said cutter shaft.

4. Machine according to claim 1, said auxiliary wheel means being provided at each end of said cutter shaft.

5. Machine according to claim 1, said supporting means comprising a fixed member and a relatively movable member, said fixed member being carried by said frame member, said auxiliary wheel being carried by said relatively movable member, and means for securing said relatively movable member to said fixed member in adjusted position.

6. Machine according to claim 5, said fixed member comprising a bracket carried by said frame member for sup orting said fixed and relatively movable members an said auxiliary wheel beyond t e outer end of said cutter shaft.

7. Machine according to claim 5, said cutter shaft having a bearing support, and means for securing said fixed member to said bearing support. 

1. A pavement cutting machine comprising a carriage having a longitudinal axis, a frame member associated with said carriage, said frame member having a cutter having a shaft extending transversely of said axis, said carriage having front wheel means in front of said cutter and rear wheel means at the rear of said cutter, auxiliary wheel means including an auxiliary wheel rotatable on an axis below and substantially parallel to the axis of said cutter shaft, and means for supporting said auxiliary wheel with the bottom of its periphery above and out of contact with the pavement, in position to contact the pavement and limit the depth of cut of said cutter when said front wheel means encounters an abrupt drop in the level of the pavement.
 2. Machine according to claim 1, said supporting means for said auxiliary wheel means comprising means for adjusting the vertical position of said auxiliary wheel means to a position slightly above a plane tangent to the bottom of said front and rear wheel means.
 3. Machine according to claim 1, said supporting means for said auxiliary wheel means comprising bracket means carried by said frame member for supporting said auxiliary wheel beyond the outer end of said cutter shaft.
 4. Machine according to claim 1, said auxiliary wheel means being provided at each end of said cutter shaft.
 5. Machine according to claim 1, said supporting means comprising a fixed member and a relatively movable member, said fixed member being carried by said frame member, said auxiliary wheel being carried by said relatively movable member, and means for securing said relatively movable member to said fixed member in adjusted position.
 6. Machine according to claim 5, said fixed member comprising a bracket carried by said frame member for supporting said fixed and relatively movable members and said auxiliary wheel beyond the outer end of said cutter shaft.
 7. Machine according to claim 5, said cutter shaft having a bearing support, and means for securing said fixed member to said bearing support. 